Capsule for preparation of a beverage

ABSTRACT

The present invention is directed to a capsule ( 1 ) for delivering a drink by injecting a pressurized fluid into the capsule comprising: a hollow body and an injection wall ( 4 ) which is impermeable to liquids and to gas and which is attached to the body and adapted to be punctured by an injection means ( 2 ) foreign to the capsule, a chamber ( 5 ) containing a bed of at least one food substance to be extracted, means ( 7, 9, 10 ) for retaining the internal pressure in the said chamber, said means comprising a pierceable membrane ( 7 ), characterized in that said capsule ( 1 ) further comprises a secondary means ( 12 ) for maintaining the bed of substance at a distance d from said pierceable membrane ( 7 ), said distance d being at least 1 mm, preferably at least 2 mm, more preferably at least 3 mm, and in that the pressure retaining means comprise: the pierceable membrane ( 7 ), raised elements ( 9 ) which open the said membrane ( 7 ) in order to create punctures and allow the liquid extract to pass through the punctures; the punctures in the membrane ( 7 ) being obtained under the effect of the rise in pressure in the chamber ( 5 ) of the capsule ( 1 ).

FIELD OF THE INVENTION

The present invention concerns a capsule for the preparation ofbeverages in a beverage preparation machine, involving a high pressureextraction and/or dissolution.

BACKGROUND OF THE INVENTION

The present invention is directed to a capsule (that is preferably acompletely closed capsule although one its walls might be open), for usein a beverage preparation machine. The machine comprises a receptaclefor accommodating said capsule and a fluid injection system forinjecting a fluid, preferably water, under pressure into said capsule.Water injected under pressure in the capsule, for the preparation of acoffee beverage according to the present invention, is preferably hot,that is to say at a temperature above 70° C. However, in some particularinstances, it might also be at ambient temperature. The pressure insidethe capsule chamber during extraction and/or dissolution of the capsulecontents is typically about 1 to 6 bar for dissolution products, 2 to 12bar for extraction of roast and ground coffee. Such a preparationprocess differs a lot from the so-called “brewing” process of beveragepreparation—particularly for tea and coffee, in that brewing involves along time of infusion of the ingredient by a fluid (e.g. hot water),whereas the beverage preparation process allows a consumer to prepare abeverage, for instance coffee within a few seconds.

The principle of extracting and/or dissolving the contents of a closedcapsule under pressure is known and consists typically of confining thecapsule in a receptacle of a machine, injecting a quantity ofpressurized water into the capsule, generally after piercing a face ofthe capsule with a piercing injection element such as a fluid injectionneedle mounted on the machine, so as to create a pressurized environmentinside the capsule either to extract the substance or dissolve it, andthen release the extracted substance or the dissolved substance throughthe capsule. Capsules allowing the application of this principle havealready been described for example in applicant's European patent n° EP1 472 156 B1, and in EP 1 784 344 B1.

Machines allowing the application of this principle have already beendescribed for example in patents CH 605 293 and EP 242 556. According tothese documents, the machine comprises a receptacle for the capsule anda perforation and injection element made in the form of a hollow needlecomprising in its distal region one or more liquid injection orifices.The needle has a dual function in that it opens the top portion of thecapsule on the one hand, and that it forms the water inlet channel intothe capsule on the other hand.

When the beverage to be prepared is coffee, one interesting way toprepare the said coffee is to provide the consumer with a capsulecontaining roast and ground coffee powder, which is to be extracted withhot water injected therein.

Capsules have been developed for such an application, which aredescribed and claimed in applicant's European patent EP 1 784 344 B1, orin European patent application EP 2 062 831.

In short, such capsules comprise typically:

-   -   a hollow body and an injection wall which is impermeable to        liquids and to air and which is attached to the body and adapted        to be punctured by e.g. an injection needle of the machine,    -   a chamber containing a bed of roast and ground coffee to be        extracted,    -   an aluminium membrane disposed at the bottom end of the capsule,        closing the said capsule, for retaining the internal pressure in        the chamber, the said membrane being associated with piercing        means for piercing dispensing holes in the said aluminium        membrane when said internal pressure inside the chamber reaches        a certain pre-determined value,    -   optionally, means configured to break the jet of fluid so as to        reduce the speed of the jet of fluid injected into the capsule        and distribute the fluid across the bed of substance at a        reduced speed.

The jet-breaking means comprises an injection space between theinjection wall and the chamber allowing the injection needle to inject ajet of pressurized fluid to be introduced through the injection wall.The distributing and jet-breaking means further comprises at least onepunctured wall which separates the injection space from the chambercontaining the bed of substance and the perforated wall is positioned,in order to keep the bed of substance in compression in the non-hydratedstate of the substance.

It was found that in such coffee capsules, pressure inside the capsulechamber increases during extraction/dissolution by the injection fluidby the fact that the self-opening system present at the bottom of thecapsule—which is an excellent system to guarantee the product freshnessthroughout storage—builds a pressure inside the capsule when fluid isinjected therein. This is due to the mechanical resistance of thealuminum membrane, which is pierced by the piercing means only aftersome pressure inside the capsule pushes said membrane onto the piercingmeans. The pressure necessary to open the membrane can be varied byselecting a material having a lower resistance (thinner aluminum forinstance). However the membrane thickness cannot be decreased below acertain level, so as not to comprise its gas, and light properties.

It was found that this effect of pressure build-up inside the capsulebefore it self-opens, is increased by the fact that the smallest coffeeparticles (so-called “fines”) present in the mass of roast and groundcoffee powder, move downwards during circulation of the extraction fluidinside the capsule chamber, and clog the dispensing holes of thealuminum membrane that is present at the bottom part of the membrane. Inthat case, liquid circulation is slowed-down, and fluid pressure insidethe capsule builds-up even more, as the pump of the machine continues toinject fluid inside the capsule chamber.

The purpose of the present invention is to obviate the aforementionedproblems, and provide a capsule allowing preparation of a brew-like(i.e. low-pressure coffee, that is to say between 1 and 3 bar) beveragewithout—or at least with very little—foam, in a capsule comprising aself-opening freshness system as described above.

SUMMARY OF THE INVENTION

The purpose mentioned above is met with the present invention, with acapsule for delivering a drink by injecting a pressurized fluid into thecapsule comprising:

-   -   a hollow body and an injection wall which is impermeable to        liquids and to gas and which is attached to the body and adapted        to be punctured by an injection means foreign to the capsule,    -   a chamber containing a bed of at least one food substance to be        extracted,    -   means for retaining the internal pressure in the said chamber,        said means comprising a pierceable membrane,    -   characterized in that said capsule further comprises a secondary        means for maintaining the bed of substance at a distance d from        said pierceable membrane, said distance d being at least 1 mm,        preferably at least 2 mm, more preferably at least 3 mm, and in        that the pressure retaining means can comprise:    -   the pierceable membrane,    -   raised elements which open the said membrane in order to create        punctures and allow the liquid extract to pass through the        punctures; the punctures in the membrane being obtained under        the effect of the rise in pressure in the chamber of the        capsule.

The invention provides a solution to prepare a product havingfilter-coffee taste and look, while preparing the cup using ahigh-pressure machine. According to the invention, the new capsule ofthe present invention allows to decrease the pressure inside the capsulechamber, with minimum mixing/shearing of coffee. Hence, in thisinvention coffee is separated from the Aluminum membrane. The coffeethus produced has very little foam (also called “crema”), or no foam atall.

In one preferred embodiment of the present invention, the capsule whichfurther comprises means configured to break the jet of fluid so as toreduce the speed of the jet of fluid injected into the capsule anddistribute the fluid across the bed of substance at a reduced speedwherein it comprises an injection space between the injection wall andthe chamber allowing the injection means to inject at least one jet ofpressurized fluid to be introduced through the injection wall, whereinthe distributing and jet-breaking means comprise at least one puncturedwall which separates the injection space from the chamber containing thebed of substance and the perforated wall is positioned in order to keepthe bed of substance in compression in the non-hydrated state of thesubstance. By non-hydrated it is meant state of the coffee powder priorto the extraction fluid wetting the mass of coffee.

Advantageously, the wall can comprise welding edges which are weldedagainst the internal surface of the hollow body in such a way as toposition the said wall back from the injection wall.

Preferably, the wall is a deformable flexible film.

Also preferably, the openings of the perforated wall are distributedsubstantially uniformly across the wall so as to distribute the streamof fluid substantially uniformly across the bed of substance

In this case, the raised elements are preferably distributed over aplate which comprises ducts leading to openings, passages or slotsthrough which the drink can flow

In any case, the secondary means can advantageously comprise aperforated wall chosen from a plastic or fiber wall with holes, a filmwith holes, a grating, a layer of woven or nonwoven material, a porouslayer or a combination thereof.

In one possible embodiment, the space between the secondary means andthe pierceable membrane comprises a layer or mass of discrete elementsfor instance a layer of granulate inert material to limit thedeformation of the secondary means during the beverage preparation. Sucha layer or mass of discrete elements, allows to keep the secondary meansat a distance from the pierceable membrane, whatever the conditions ofpressure inside the capsule, and even though fluid circulates withinsaid capsule; at the same time, the said layer or mass allows tocompletely let the extraction/dissolution fluid circulate, due thespaces between the discrete elements.

In a particularly preferred embodiment of the present invention, thecapsule chamber containing the bed of substance to be extracted and/ordissolved, is divided by at least one dividing wall into at least twocorresponding compartments, each containing one type of substance to beextracted and/or dissolved in an at least partially sequential manner.

In the latter embodiment, the compartments preferably comprise an uppercompartment containing a powdered soluble coffee to be dissolved toproduce a liquid coffee solution, and a lower compartment containing amass of roast and ground coffee to be extracted under pressure by saidliquid coffee solution.

Also, at least one of the compartments advantageously encloses a bed ofsubstance to be extracted and/or dissolved, such that said substance isin a compressed state at least at the time pressurized fluid circulatesthrough said substance.

BRIEF DESCRIPTION OF THE DRAWINGS

Additional features and advantages of the present invention aredescribed in, and will be apparent from, the description of thepresently preferred embodiments which are set out below with referenceto the drawings in which:

FIG. 1 is a schematic profile cut view of a capsule according to theinvention;

FIG. 2 is a schematic profile cut view of an alternative embodiment of acapsule according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

In the following detailed description, the embodiment considers that thecapsule according to the invention comprises coffee, in roast and groundand/or soluble powder form. However, the capsule as described herebelowcould be filled with any other food ingredient that would be suitablefor being extracted and/or dissolved by a fluid under pressure, in abeverage preparation machine described in preamble. Such ingredients canbe in gel, concentrate, powder or particulate soluble form and includebut are not limited to: tea, dehydrated soup, milk powder, infantformula powder, fruit juice concentrate, dairy creamers, sweeteningingredients, natural or artificial, cocoa-based ingredients, spices,meat, fish, vegetable ingredients, and mixtures thereof.

Illustrated in FIG. 1, is a capsule 1 for delivering a drink byinjecting a pressurized fluid into said capsule. The injection is doneby placing the capsule into a machine (not illustrated in the drawing),which machine comprises a needle 2 through which a extraction fluid ispumped under pressure (illustrated by a dashed arrow), and injected inthe capsule.

The capsule 1 comprises a hollow body 3 and a top injection wall 4 whichis a flexible membrane welded onto the capsule body 3, the said membrane4 being impermeable to liquids and to gas. The top membrane wall 4 isadapted to be punctured by the needle 2.

The capsule 1 further comprises a chamber 5 containing a bed of at leastone food substance 6 to be extracted.

The chamber 5 of the capsule is closed at its bottom side by means forretaining the internal pressure in the said chamber. This pressureretaining means comprises:

-   -   a pierceable aluminum membrane 7 that is sealed onto an edge 8        in the lower part of the capsule, and    -   raised elements 9 to create punctures through the membrane 7 and        allow the liquid extract produced inside the capsule to pass        through the said punctures; the raised elements are        pyramid-shaped pins 9 which are distributed over a plate 10. The        plate 10 comprises ducts (not illustrated in the drawing)        leading to a dispensing opening 11 of the capsule through which        the prepared liquid drink can flow.

Punctures in the membrane 7 are obtained under the effect of the rise inpressure in the chamber of the capsule, which presses said membrane 7against the pins 9 of the plate 10, such that the pins perforate themembrane. The membrane is made in aluminum and has a thickness comprisedbetween 5 and 50 μm, preferably between 10 and 45 μm, and mostpreferably a thickness comprised between 25 and 40 μm. The thicker themembrane, the higher the pressure inside the capsule to allow aperforation of the membrane, and hence, the higherdissolution/extraction pressure inside the capsule chamber.Particularly, it was found that the thinner the bottom aluminummembrane, the lower the pressure. Specific piercing plate should be ableto create holes on Aluminum easily without the need for building a highpressure inside the capsule.

In the example described with reference to FIG. 1, the thickness of thealuminum membrane 7 is chosen such that the extraction pressure insidethe capsule chamber 5 before the said membrane is open by the pins 9 isbetween 0.1 and 3 bars (relative pressure), preferably between 1 and 3bar (relative pressure). According to the invention, the capsule 1comprises secondary means 12 for maintaining the bed of substance 6 at adistance d from said pressure-retaining means 8, 9, 10. In the example,said distance d is 3 mm.

As illustrated in FIG. 1, the secondary means 12 comprise a perforatedwall which is a membrane with holes having a diameter not greater than500 μm. Particularly, it was found that it is important that roast andground (R&G) coffee fines cannot reach the Aluminum membrane becausethis would increase the internal pressure inside the capsule by cloggingat least partially the dispensing holes pierced through said aluminummembrane, as previously explained: the R&G average size is 150 to 1000μm, with an average particle size of 500 μm. More precisely, themembrane 12 is manufactured from filter paper, of the type used forproducing tea bags. It could alternatively be manufactured from anon-woven material.

The effect of the filter membrane 12 is to remove foam in the finalproduct that flows out of the capsule. It was found that foam is removedby the conjunction of two effects: first, the filtering effect of themembrane 12 breaks air bubbles within the liquid, this effect beingreinforced by the fact that a free space is created in the distancebetween the aluminum bottom membrane 7, and the filter membrane 12. Thefilter membrane could be made of woven polymer.

The second effect, is the fact that the filter membrane 12 preventssmallest coffee particles (“fines”) to flow with the liquid coffee thatis produced inside the capsule chamber, and clog the aluminum membrane 7at the time the latter is pierced by the pyramid pins 9. It was foundthat in known capsules, the fines are moved towards with the liquidcirculation in the roast and ground coffee mass, and clog the holes ofthe aluminum membrane, once the latter is opened. The result is anincrease of pressure inside the capsule, due to the fact that liquid isprevented from correctly flowing out of the capsule. Such a pressureincrease produces coffee foam (“crema”). This crema is characteristic ofespresso-like coffee, but is undesirable when a brew-like coffeeproduction is sought. With the present invention, it was made possibleto produce a brew-like coffee cup (i.e. long cup, made with low pressureand no foam) from a closed capsule.

The capsule 1 illustrated in FIGS. 1 and 2 further comprises aliquid-permeable wall 13 configured to break the jet of fluid injectedby the needle into the capsule, so as to reduce its speed, anddistribute the said fluid across the bed of substance 6 in a evenmanner. The jet-breaking wall 13 is positioned in the capsule so as tocreate an injection space 14 between the injection wall 4 and thechamber 5 that contains the ingredient or ingredients 6 to be extractedand/or dissolved.

In this case the needle injects the pressurized fluid through theinjection wall into the headspace 14, and the distributing andjet-breaking wall 13 separates the said injection space 14 from thechamber 5 containing the bed of substance 6.

Importantly, the bed of substance 6 is held in a compressed state in thenon-hydrated state of said substance, between the jet-breaking wall 13on top, and the filter membrane 12 at the bottom. The wall 13 andmembrane 12 are made of materials which are permeable only to liquidsand gas, but not to solids (even very fine particles).

The jet-breaking liquid permeable wall 13 comprises welding edges whichare welded against the internal surface of the hollow body 3 of thecapsule.

The liquid permeable openings of the perforated wall 13 are distributedsubstantially uniformly across the wall so as to distribute the streamof fluid substantially uniformly across the bed of substance 6.

FIG. 1 shows the proposed new capsule design for filter coffee. Coffeeis placed between two plastic membranes which comprise many small holesthrough which a liquid can flow, but which are sufficiently small toprevent passage of solid particles, even small fine particles, likesmall roast and ground coffee or soluble coffee particles.

According to an essential requirement of the invention, coffee containedwithin the capsule chamber is not in direct contact with the Aluminumbottom membrane, would it be soluble, or roast and ground coffee, or amixture thereof. The piece above the coffee is to distribute the waterevenly. However, it is not necessary to have this piece if coffeeparticle size is large enough and if coffee is loose.

In FIG. 2 is shown a capsule 1 which is very close in its constructionto the capsule already described above with reference to FIG. 1.However, in this particular embodiment, the capsule comprises a dividingwall 15, which separates the chamber containing ingredients to beextracted/dissolved in one upper compartment 16 and one lowercompartment 17, both being superimposed. The dividing wall ismanufactured such that no solid, even fine particles can pass throughone compartment to another, but the wall 15 is liquid permeable.

In this case, when an extraction fluid is injected through the needle 2within the headspace 14, it then passes through the jet-breakingliquid-permeable wall 13, into the upper compartment 16. In thiscompartment 16, the fluid interacts with powdered soluble coffee, anddissolves the latter to produce a liquid coffee solution, which thencirculates through the perforated liquid-permeable dividing wall 15,towards the lower compartment 17. The lower compartment 17 contains amass of roast and ground coffee, which is extracted by the liquid coffeesolution prepared in the upper compartment. Solids of the roast andground coffee are extracted by the liquid coffee at a pressure of about1 to 3 bars (relative pressure). Such a pressure allows a goodextraction of the coffee solids from the roast and ground coffee powderparticles, and sensory tests have shown that the final product thusobtained is particularly rich in terms of flavour profile and tastebody. With a multi-compartment capsule as shown in FIG. 2, it ispossible to produce a long cup of coffee (at least 25 cl., preferablybetween 33 cl. and 50 cl., using a capsule which contains less than 20gram of coffee ingredient, and especially less than 15 gram of roast andground coffee. Such a construction is therefore particularly interestingas the capsule size remains small, while allowing a consumer to producea long cup of coffee having a very pleasant taste and body profile. Theresult product in cup is a so-called “brew-like” coffee that is to saywithout foam.

In all cases, and particularly in the examples described in detailabove, it is preferable to use large particle size coffee with thisdesign to prevent small particles (so-called “fines”) clogging the holesof the filter membrane 12. As it is difficult to avoid all coffee finesafter grinding, a non-woven type plastic filter or a filter with smallholes can be added to the design or can replace the plastic piece withholes as shown in FIG. 1. In one of the capsules tested by theapplicant, the pore size of the filter material was 100 microns.

It should be understood that various changes and modifications to thepresently preferred embodiments described herein will be apparent tothose skilled in the art. Such changes and modifications can be madewithout departing from the spirit and scope of the present invention andwithout diminishing its attendant advantages. It is therefore intendedthat such changes and modifications be covered by the appended claims.

1. Capsule for delivering a drink by injecting a pressurized fluid intothe capsule comprising: a hollow body and an injection wall which isimpermeable to liquids and to gas and which is attached to the body andadapted to be punctured by an injector that is not part of the capsule;a chamber containing a bed of at least one food substance to beextracted; a member for retaining the internal pressure in the chamber,the member comprising a pierceable membrane; the capsule furthercomprises a secondary member for maintaining the bed of substance at adistance from the pierceable membrane the distance being at least 1 mm,the retaining member comprising: the pierceable membrane; and raisedelements which open the membrane in order to create punctures and allowthe liquid extract to pass through the punctures, the punctures in themembrane being created due to the effect of the rise in pressure in thechamber of the capsule.
 2. Capsule according to claim 1, comprising amember configured to break the jet of fluid so as to reduce the speed ofthe jet of fluid injected into the capsule and distribute the fluidacross the bed of substance at a reduced speed wherein it comprises aninjection space between the injection wall and the chamber of thecapsule that contains the bed of substance, allowing the injector toinject at least one jet of pressurized fluid to be introduced throughthe injection wall, wherein the distributing and jet-breaking membercomprise at least one punctured wall which separates the injectionheadspace from the chamber containing the bed of substance, and theperforated wall is positioned in order to maintain the bed of substancein compression in the non-hydrated state of the substance.
 3. Capsuleaccording to claim 2, wherein the wall comprises welding edges which arewelded against the internal surface of the hollow body of the capsule insuch a way as to position the wall back from the injection wall. 4.Capsule according to claim 2, wherein the wall is a deformable flexiblefilm.
 5. Capsule according to claim 2, wherein the openings of theperforated wall are distributed substantially uniformly across the wallso as to distribute the stream of fluid substantially uniformly acrossthe bed of substance
 6. Capsule according to claim 1, wherein the raisedelements are distributed over a plate which comprises ducts leading toopenings, passages or slots through which the drink can flow.
 7. Capsuleaccording to claim 1, wherein the secondary member comprises aperforated wall selected from the group consisting of a plastic wallwith holes, a film with holes, a grating, a layer of woven or nonwovenmaterial, a porous layer and combinations thereof.
 8. Capsule accordingto claim 1, wherein the space between the secondary member and thepierceable membrane comprises a layer or mass of discrete elements tolimit the deformation of the secondary means during the beveragepreparation.
 9. Capsule according to claim 1, wherein the chambercontaining the bed of substance to be extracted and/or dissolved, isdivided by at least one dividing wall into at least two correspondingcompartments, each containing one type of substance to be extractedand/or dissolved in an at least partially sequential manner.
 10. Capsuleaccording to claim 9, wherein the compartments comprise an uppercompartment containing a powdered soluble coffee to be dissolved toproduce a liquid coffee solution, and a lower compartment containing amass of roast and ground coffee to be extracted under pressure by saidliquid coffee solution.
 11. Capsule according to claim 9, wherein atleast one of the compartments encloses a bed of substance to beextracted and/or dissolved, such that the substance is in a compressedstate at least at the time pressurized fluid circulates through saidsubstance.